scholarly journals On the duality of space trusses and plate structures of rigid plates and elastic edges

2020 ◽  
Vol 35 (4) ◽  
pp. 135-146
Author(s):  
Tamás Baranyai
Keyword(s):  
Plate Structures ◽  
Plate Structure ◽  
Indeterminate Structures ◽  
Space Trusses

Dualities have been known to map space trusses and plate structures to each other since the 1980s. Yet the computational similarity of the two has not been used to solve the unfamiliar plate structure with the methods of the well-known truss. This article gives a method to find the forces and displacements of a plate structure with rigid plates and elastic edges, using a dual truss. The plates are assumed to be rigid in their respective planes only and deformable otherwise. The method provided is applicable for both statically determinate and indeterminate structures, subjected to both statical and kinematical loads.

scholarly journals Improvement on sound transmission loss through a double-plate structure by connected with a mass–spring–damper system

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401771394 ◽  
Author(s):  
Qibo Mao ◽  
Hui Shen
Keyword(s):  
Resonance Frequency ◽  
Natural Frequency ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Sound Transmission Loss ◽  
Plate Structures ◽  
Air Mass ◽  
Plate Structure ◽  
Global Cost ◽  
Mass Spring

It is well-known that the acoustic performance of double-plate structures deteriorates rapidly around the mass–air–mass resonance frequency. In this study, a mass–spring–damper system connected between incident and radiating plates is used to improve the sound transmission loss at low-frequency ranges. First, a full structural-acoustic modal coupling model is developed to analyze the vibration and acoustical behaviour of the double-plate structures with mass–spring–damper system. Because there are in-phase or out-of-phase vibrations between double plates, tuning the natural frequency of the mass–spring–damper system exactly to the mass–air–mass resonance frequency cannot guarantee the maximum improvement on transmission loss. Optimal natural frequency and mass of the mass–spring–damper system were found as a solution of optimization problem with a global cost function defined as frequency-averaged sound transmission loss in the desired frequency range (around mass–air–mass resonance frequency). Finally, some numerical calculation results are presented. The calculated results show that the sound transmission loss of a double-plate structure can be improved significantly using optimally tuned mass–spring–damper system. The results indicate that an overall improvement of 12 dB below 1000 Hz can be achieved when the mass of the mass–spring–damper system equals to 10% weight of the double-plate structure.

scholarly journals Detection of Cavities Beneath Plate Structure using a Microphone

2020 ◽  
Vol 20 (6) ◽  
pp. 229-237
Author(s):  
Seonghun Kang ◽  
Jong-Sub Lee ◽  
Jung-Doung Yu ◽  
Sang Yeob Kim
Keyword(s):  
Flexural Vibration ◽  
Signal Amplitude ◽  
Laboratory Model ◽  
Sound Waves ◽  
Plate Structures ◽  
Plate Structure ◽  
Acrylic Plate ◽  
Model Chamber ◽  
Dry Soil ◽  
Measurement Location

Failure of plate structures such as pavements can be caused by the occurrence of cavities beneath the structure. In this study, a cavity beneath the plate structure were detected in a laboratory model chamber using a hammer and microphone. Specifically, a chamber was constructed using an acrylic plate and dry soil to simulate the pavement and the subgrade, respectively. A plastic box was placed between the acrylic plate and dry soil to simulate a cavity beneath the pavement. The sound waves generated by impacting the acrylic plate with a hammer were measured using a microphone. The measured area under the rectified signal envelope (MARSE) energy was calculated for the measured sound waves, and the variation in it were analyzed according to the measurement location. The test results show that the signal attenuation was low at the cavity section owing to the conservation of impact energy and that the signal amplitude becomes lower at the soil section owing to the weakened flexural vibration. Therefore, the estimated MARSE energy at the cavity section was larger than that at the soil section. This study demonstrates the effective utilization of microphones for detecting cavities beneath the plate structures.

Investigating the Statical Stability of Pin-jointed Structures Using Genetic Algorithm

2005 ◽  
Vol 20 (1) ◽  
pp. 53-68 ◽  
Author(s):  
Sana El-Lishani ◽  
H. Nooshin ◽  
P. Disney
Keyword(s):  
Genetic Algorithm ◽  
Quadratic Form ◽  
Computer Program ◽  
Search Technique ◽  
Cable Structures ◽  
The Stability ◽  
Indeterminate Structures ◽  
Cable Nets ◽  
2D And 3D ◽  
Space Trusses

In this paper, the method of genetic algorithm is used as a search technique to find the stability characteristics of simultaneously statically and kinematically indeterminate structures The genetic algorithm is used to find out if there is a solution for a specific quadratic form which has to be satisfied in order to guarantee the statical stability. The genetic algorithm is a search technique that imitates nature in selecting and optimising towards an aim. The use of the genetic algorithm in the search for the stability of pin-jointed structures is found to be simple and powerful. A computer program called STAPS (Stability of Pin-jointed Structures) has been developed using the genetic algorithm. This program firstly identifies the independent mechanisms and states of self-stress, if any, in a structure. Then, the program searches for any state of self-stress that can stabilise all the mechanisms of the structure. STAPS program is a powerful tool for finding the stability of 2D and 3D pin-jointed structures. The program can be used for investigating the stability of space trusses and cable structures like cable nets, cable-strut and tensegrity structures1,2. Section 1 of this paper contains a brief introduction. Section 2 discusses the background of what is called ‘product forces’. Also, in Section 3 the stabilisation of mechanisms of pin-jointed structures is discussed. Section 4 introduces the method of genetic algorithm and how it is used in the search for stability of pin-jointed structures. Section 5 introduces the STAPS program together with illustrative examples of its application. Finally, Section 6 gives a conclusion of the work presented in this paper.

Design and Analysis of a Foldable Mobile Shelter System

2007 ◽  
Vol 22 (3) ◽  
pp. 161-168 ◽  
Author(s):  
Ir. arch. Niels De Temmerman ◽  
Marijke Mollaert ◽  
Ir. arch. Tom Van Mele ◽  
Ir. arch. Lars De Laet
Keyword(s):  
Degree Of Freedom ◽  
Design Parameters ◽  
Plate Structures ◽  
Plate Structure ◽  
Folding Pattern ◽  
Kinematic Behaviour ◽  
Associated Design ◽  
Plate System

A concept for a mobile shelter is proposed, based on the geometry and kinematic behaviour of foldable plate structures. The folding pattern and the associated design parameters are discussed, along with their influence on the geometry and the kinematic behaviour. It is shown that the transition can be made from a foldable plate structure to a foldable bar structure, while retaining an identical kinematic behaviour. This is done by introducing custom-built joints for connecting the bars which allow the system to deploy in the desired way, maintaining the same D.O.F (degree of freedom) as the plate system. For the structure to be employable as a fully-fledged temporary space enclosure, a lightweight textile membrane is incorporated beforehand and deployed along with the bar structure.

scholarly journals Analyse the behavior of the functionally graded material plate structures with piezoelectric patches by using isogeometric analysis

2020 ◽  
Vol 2 (SI2) ◽  
pp. First
Author(s):  
Khuong Duy Nguyen ◽  
Nguyen Manh Tien ◽  
Nguyen Ba Dat ◽  
Vu Cong Hoa
Keyword(s):  
Functionally Graded Material ◽  
Isogeometric Analysis ◽  
Order Approximation ◽  
Spline Approximation ◽  
Functionally Graded ◽  
High Order ◽  
Computational Time ◽  
Plate Structures ◽  
Plate Structure ◽  
Graded Material

This article presents the use of isogeometric analysis (IGA) to analyse the behaviour of the functionally graded material (FGM) plate structures with piezoelectric patches. This study investigates the effect of piezoelectric patches on the plate structure made of FGM material as a solid model. Because IGA is based on the NURBS (Non-uniform rational basis spline) approximation, this method describes the exact geometry with the higher-order functions approach. The effectiveness of the present method is to use the few degrees of freedom combining a high-order approximation function between elements to ensure the accuracy of the result, which reduces the computational time and saves the required memory. In addition, NURBS geometry has also been shown to be a viable approach due to the flexibility in mesh construction such as refinement and high-order continuity that warranty correctly the results of the problem. Based on the advantages that IGA has been proved by many previous studies, we built a three-dimensional model for plate structure consisting of upper and lower layers with piezoelectric patches, middle layer with FGM material. The results are verified and compared to the commercial Comsol software to prove the effectiveness of the method for this problem.

Vibration Characteristics of Plate Structures Embedded with Acoustic Black Holes and Distributed Dynamic Vibration Absorbers

2019 ◽  
Vol 24 (3) ◽  
pp. 531-539
Author(s):  
Xiuxian Jia ◽  
Yu Du ◽  
Ye Yu ◽  
Kunmin Zhao
Keyword(s):  
Vibration Response ◽  
Vibration Absorbers ◽  
Uniform Thickness ◽  
Frequency Range ◽  
Plate Structures ◽  
Design Constraint ◽  
Plate Structure ◽  
Dynamic Vibration ◽  
Dynamic Vibration Absorbers ◽  
Structural Mass

This study discusses a method of combining the acoustic black hole (ABH) concept and dynamic vibration absorbers (DVAs) together as a lightweight passive control approach for structural vibration and noise attenuation. Finite element (FE) simulations and experiments are used to compare vibration response levels of plate structures. The plate structures have been integrated with various vibration attenuation treatments including damping layers, DVAs, ABHs and ABH-DVA pairs. It is demonstrated experimentally that the plate structure integrated with two ABH-DVA pairs has the lowest overall vibration response level in the frequency range below 800 Hz. More interestingly, the total structural mass of the plate structure integrated with ABH-DVA pairs is 8.24% less than that of the uniform thickness plate. The experimental observations are further verified with simulation results. With the help of the FE model, plate structures integrated with more than two ABH–DVA pairs targeted at the simultaneous attenuation of multiple resonances are studied and compared with traditional uniform thickness plates. Under the design constraint of the total structural mass being equal, it is shown that plates integrated with DVA-ABH pairs always have lower vibration response levels in the low-mid frequency range where mechanical vibration commonly occurs.

Active Suspension Control of Elastic Car Structure

1998 ◽  
Vol 10 (1) ◽  
pp. 56-61
Author(s):  
Yasuhisa Fujisaki ◽  
◽  
Katsuaki Kodaka ◽  
Yasuhumi Kawagou ◽  
Kazuto Seto
Keyword(s):  
Active Suspension ◽  
Theory Building ◽  
Vibration Modes ◽  
Plate Structures ◽  
Plate Structure ◽  
Suspension Systems ◽  
Distributed Parameters ◽  
Active Suspension Systems ◽  
Suspension Control ◽  
Lq Control

This study discusses the vibration control of a plate structure supported with active suspension, replacing an elastic car body with a plate structure. Plate structures have typical distributed parameters. Hence, we designed a control system based on LQ control theory, building a six-particle physical model that controls the six-degree modes of bouncing, rolling, and pitching that include vibration modes of bending and torsion. These multiple modes were controlled in simulations and experiments, which verified that vibration in active suspension systems can be controlled.

A Hybrid GFDM–SBM Solver for Acoustic Radiation and Propagation of Thin Plate Structure Under Shallow Sea Environment

2020 ◽  
Vol 28 (02) ◽  
pp. 2050008
Author(s):  
Qiang Xi ◽  
Zhuojia Fu ◽  
Yudong Li ◽  
He Huang
Keyword(s):  
Thin Plate ◽  
Acoustic Radiation ◽  
Singular Boundary ◽  
Shallow Sea ◽  
Plate Structures ◽  
Coupling Vibration ◽  
Underwater Acoustic ◽  
Plate Structure ◽  
Hybrid Solver ◽  
Comsol Simulation

This paper makes the first attempt to propose a novel hybrid collocation solver based on the generalized finite difference method (GFDM) and singular boundary method (SBM) to analyze underwater acoustic radiation and propagation around the thin plate structures excited by simple harmonic force under shallow sea environment. In the proposed hybrid solver, the meshless GFDM is employed to obtain the fluid–structure coupling vibration response of thin plate structure, and then the SBM with Pekeris waveguide Green function is used to calculate the external acoustic field of thin plate structure. The simplified Price–Wu boundary condition is adopted on the surface of plate structure to connect the computational domains between the GFDM and SBM. Three benchmark examples are carried out to demonstrate the accuracy and efficiency of the proposed hybrid GFDM–SBM solver in comparison with the COMSOL simulation for computing underwater acoustic wave fields around the thin plate structures under shallow sea environment.

Power flow analysis of built-up plate structures using the dynamic stiffness method

2017 ◽  
Vol 24 (13) ◽  
pp. 2815-2831 ◽  
Author(s):  
Wenwei Wu ◽  
Xuewen Yin ◽  
Hui Li ◽  
Kuikui Zhong
Keyword(s):  
Power Flow ◽  
Dynamic Stiffness ◽  
Flow Analysis ◽  
Plate Structures ◽  
Vibration Transmission ◽  
Plate Structure ◽  
Power Flow Analysis ◽  
Stiffness Method ◽  
Dynamic Stiffness Method ◽  
Out Of Plane

The dynamic stiffness method (DSM) in our recent paper, which can consider both in-plane and out-of-plane vibrations simultaneously, is formulated to investigate the power flow characteristics of built-up plate structures. Prior to power flow analysis, comprehensive validation works on our DSM are performed so as to better exhibit its numerical capabilities. Power input and power transmission within a two-plate structure are then analyzed by following the context of in-plane and out-of-plane vibrations. In addition, three vibration transmission paths within a multiple plate structure are characterized in terms of power flow densities, which can provide better physical insights in vibration transmission within complex plate structures. Compared to power flow analysis based on the well-known reception/mobility method, our approach is strongly recommended for the dynamics of built-up structures since it can assemble the overall stiffness matrix in a straightforward manner like that in the conventional finite element technique.

scholarly journals Temperature Effect on Stability of Clamped–Clamped Composite Annular Plate with Damages

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4559
Author(s):  
Dorota Pawlus
Keyword(s):  
Annular Plate ◽  
Thermal Environment ◽  
Thermal Sensitivity ◽  
Practical Importance ◽  
Degradation Process ◽  
Temperature Fields ◽  
Diagnostic Process ◽  
Plate Structures ◽  
Plate Structure ◽  
Temperature Field Model

The paper presents the response of a three-layered annular plate with different damaged laminate facings to the action of the static or dynamic temperature field model. Various damages of laminate, composite facings change the plate structure reaction under the temperature fields. Obtained results indicate practical meaning of analyses in failure diagnostic process. The thermal sensitivity of two kinds of plate structures, undamaged and damaged, offers both new practical and scientific possibilities in evaluation of the plate behavior. The relations between macro-damage, i.e., the buckling of the plate structure and micro-damages of plate layers subjected to temperature gradient, are shown. The numerical solution is proposed as the most effective in examinations of the various transversally symmetrical and asymmetrical plate structures with a different rate of damages. The graphical distribution of changes in values of static and dynamic critical loads illustrate the process of structural damaging during its exploitation. They have practical importance in the evaluation of the structure capacity. The knowledge of the effect of laminate degradation process on plate buckling phenomenon located in thermal environment complements previous investigations and designates complex, multi-parameter problems as having scientifically new elements.

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